I. Field of the Invention
The present invention relates to a system for locating a hole in an underlying member to enable an aligned hole to be drilled into an overlying member from the side of the overlying member.
In some manufacturing processes it is customary to locate and drill fastening holes in a major component, then position a minor component over the hole so as to drill a mating hole in the minor component. However, in some instances, after the fastening holes are drilled in the major component, it assumes a position, beneficial for other reasons, which prevents the use of drill in a manner in which the existing hole could serve as a guide to drill the mating hole in the minor component. This situation requires that the hole be drilled from the side of the minor component which overlies, and therefore hides, the hole in the major component.
II. Description of the Prior Art
There is substantial evidence in the prior art of attempts to perform operations on one side of an opaque barrier which are necessarily dependent upon the position of an object behind that barrier. For example, in the patent to Bloomfield, U.S. Pat. No. 2,318,191, electromagnets are used to position and maintain a pair of objects in an aligned fashion on opposite sides of sheet material so that they can be riveted together to form a unitary structure.
U.S. Pat. No. 2,933,679 to Bray discloses a well known stud finder device which utilizes an elongated magnet which is permitted to pivot as its casing is drawn across a wall, the magnet being attracted to the head of nails which have been driven into studs to which the sheet rock is attached.
In the patent to Cunningham, U.S. Pat. No. 2,834,938, a ball on one side of a wall of varying thickness is attracted to a magnet on the opposite side of the wall. As the magnet is drawn along the wall, the ball moves with it and an ammeter of an associated electrical circuit provides a reading which is proportional to the thickness of the wall.
Another disclosure involving metal balls is presented in U.S. Pat. No. 4,741,534 to Rogahn. In this instance, each ball is placed in a spherical chamber within a cube and attracted to a magnetic base. Multiple blocks are thereby mounted on the base to form a picture puzzle or the like.
In U.S. Pat. No. 3,793,738 to Blakey and in U.S. Pat. No. 3,722,360 to Blakey et al., magnets are used for locating and positioning a part on a surface plate and enabling the replacement of the part with another part of the same configuration.
In U.S. Pat. No. 4,384,396 to Smolik, the position of an electrical receptacle box behind a wall is determined, then an opening cut in the wall to enable a cover to be subsequently placed over the opening into the receptacle box.
In U.S. Pat. No. 4,388,890 to Wester et al., a magnet temporarily mounted on one side of a wall serves to attract another magnet with a drill guide therein positioned on the opposite side of the wall. When the two magnets are aligned, which can only be achieved on a trial and error basis, and not with any visual assurance, a hole is then drilled into the wall using the hole in the guide.
It was in light of the prior art, typical examples of which have just been described, that the present invention was conceived and has now been reduced to practice.